US engineer caught on camera poisoning colleague’s water bottle

A California chemical engineer, David Xu, was caught on camera allegedly poisoning his colleague, Rong Yuan, through her water bottle. Xu, a metallurgist at Berkeley Engineering and Research, allegedly tampered with Yuan's water bottle with a toxic heavy metal, cadmium, for nearly 18 months between 2017 and 2019. The footage, recorded by Yuan in 2019, shows Xu putting a substance into her water bottle.

Laboratory tests confirmed the presence of cadmium in the bottle, exceeding the federal limit for drinking water by up to 3.5 million times. Yuan began experiencing severe health problems, including violent vomiting, in 2017 and reportedly felt close to death multiple times. After initially advising Yuan to work from home, Xu eventually tampered with her water bottle.

The poisoning was uncovered in early 2019 after Yuan installed a hidden camera at her desk. Xu was arrested in March 2019 and pleaded no contest to poisoning in September 2023, receiving probation and credit for one day in custody. Yuan, who suffered long-term health effects from the poisoning, is now seeking to have her felony conviction dismissed.